Sink-float separatory apparatus



June 26, 1956 R. SCHREIBER ETAL SINK-FLOAT SEPARATORY APPARATUS 3Sheets-SheenI 1 Filed Aug. 17. 195s INVENTORS RUDULF 5CH/FUEL? June 26,1956 R. SCHRElBER ETAL. 2,752,040

SINK-FLOAT SEPARATORY APPARATUS 5 Sheets-Sheet 2 GER/#IRT W SCI/UE TZJune 26, 1956 R. SCHREIBER ET A1. 2,752,040

SINK-FLOAT SEPARATORY APPARATUS 17. 1953 3 Sheets-Sheet 3 Filed Aug.

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INVENTORS RUDOLF SCHE/EER GEPHT W. SCHUETZ SNK-FLOAT SEPARATORYAPPARATUS Rudolf Schreiber, Manhasset, and Gerhart W. Schuetz, New York,N. Y., assignors to The Ore & Chemical Corporation, New York, N. Y., acorporation of New York Application August 17, 1953, Serial No. 374,686

7 Claims. (Cl. 209-173) The invention relates to apparatus for gravityseparation of materials, as in coal cleaning, ore beneticiation,classification of solids, and for other uses.

Summary Apparatus of the kind to which our invention relates operates onthe general principle of gravity separation in liquid media. When theliquid medium consists of water and iinely ground materials such as, forexample, finely ground magnetite, ferrosilicon or galeria mixed to aspecic gravity which oats one component of the feed material and permitsanother component to sink, the process performed with theuse of thesink-oat apparatus is generally referred to as dense media or heavymedia separation.

Gravity separation has generally been performed herctofore withapparatus Classifiable under three type headings, viz cone-typeseparators, drum-type separators and screw-type classifiers. With thelast-named apparatus, the usual objective is the gravity separation ofcoarse particles from fine in a water suspension, and the apparatus iscalled a classifier because it makes a classification of solidsaccording to size through the difference in settling rate of diiferentsize particles in suspension. For many purposes the cone-type separatorhas long been preferred over the others, but it has certain recognizeddisadvantages such as the limitation it imposes on the maximum size ofthe component which sinks in the medium (commonly referred to as thesink),. This limitation on size of the sink material which can behandled arises by reason of the fact that when the sink fragments becometoo large their removal from the bottom of the cone is difficult.Generally this removal is effected by an air lift which comprises a pipethrough which compressed air iiows in an upward direction, lifting thesink from the apex at the bottom of the cone up to a discharge point ator beyond the rim of the cone. Sometimes a mechanical bucket conveyorlift is used in place of an air lift in an effort to overcome thelimitation on sink fragment size, but this introduces complications ofdesign, construction, cleaning and maintenance.

Drum separators overcome the limitation on size of sink fragments, butintroduce other problems. In general, this type of separatory vesselcomprises a cylindrical drum which rotates on a horizontal axis. Aseries of vanes around the inside of the rotating drum lift the sink toa discharge point above a chute which extends in a generally axialdirection from within the drum to a point beyond one end of the drum.This apparatus requires the use of heavy rotating parts and gives riseto diiiicult problems of cleaning and maintenance. Also the vanes, whichcontinually rotate through the pool area, create eddy currents whichinterfere with the sinking and oating separatory action. Furthermore,the fact that with this type of apparatus both the sink and the oat mustbe removed from the end of the drum, i. e. axially, creates designproblems and limits the pool area.

2,752,040 Patented June 26, 1956 Screw-type classifiers have onlylimited application to sink-float processes, being designed primarilyfor other purposes. These classifiers are large, taking up a greatamount of oor space, and are expensive to build and maintain.

lt is an object of our invention to provide apparatus for sink-floatseparation, or classification of solids, which overcomes or minimizesthese and other difficulties inherent in separatory apparatus of theseveral types described above or in other forms of apparatus heretoforeknown. According to our invention there is provided a vessel which is ofgenerally arcuate form in vertical section, a rake movable back andforth in a generally arcuate path within the vessel to move sunkenmaterial from the bottom of the vessel to discharge outlets at therespective ends of the arcuate path, and a discharge weir for iioatingmaterial. Arranged within the vessel is a bale encircling a pool forfloating material, and the rake is mounted on an oscillatory supportingarm which extends between the baille and the sides of the vessel. Thesupporting arm extends for some distance in the general direction of thearcuate path of movement of the rake and thence radially with respect tosuch path to a pivotal mounting above the vessel. A troughk extendsfrorn the discharge Weir to receive material suspended in the liquidmedium, which suspended material may comprise either iloating material,or 'due particles which have not had time to settle out, or both. Whenthe rake is at one end of its arcuate path of movement, this troughextends above the supporting arm of the rake. Other features of ourinvention will appear as the description proceeds. Y

Description With reference to the accompanying drawings we shall now setforth the best mode contemplated by us for carrying out our invention.

Fig. l is a view of our preferred form of apparatus, showing theseparatory vessel and associated structure in vertical section and theoperating mechanism in front elevation as generally indicated by theline 1-1 in Fig. 2.

Fig. 2 is a vertical sectional view of the same apparatus, taken asindicated at 2 2 in Fig. 1.

Fig. 3 is a plan view of the separatory vessel and associated structuretaken as indicated at 3 3 in Fig. 1.

Fig. 4 is an enlarged detail sectional View of the rake and an adjacentportion of the vessel, showing the rake at the mid-point of its travelin one direction.

Fig. 5 is a diagrammatic view of the automatic control for the operatingmechanism.

Our improved separatory apparatus comprises a vessel 6 of generallyarcuate form in vertical section, a rake 7 movable back and forth in agenerally arcuate path, as indicated by the arrows a, a', to move sunkenmaterial S from the bottom of the vessel to discharge outlets 8, 8 atthe respective ends of the arcuate path, and a discharge weir 9 formaterial suspended in the liquid medium. Arranged within the vessel is abaiiie 10 encircling a pool 11 for iioating material F, and the rake 7is mounted on one or more oscillatory supporting arms 12 which extendbetween the baffle and the sides 13 of vessel 6. The sup porting arms 12extend for some distance in the general direction of the arcuate path ofmovement of the rake, as at 14, and thence radially with respect to suchpath, as at 15, to a pivotal mounting 16 above the vessel. A trough 17extends from the discharge weir 9 for the oating material. When the rake7 is at one end of its arcuate path of movement, as shown in Fig. l,trough 17 extends above the supporting arms 12, the arrange.- ment beingsuch that the rake may be brought slightly above the discharge weir 9for the floating material to carry the sink to the edge of weir S fordischarge from the vessel without interference with either the floattrough 17 or the baflie 10.

Vessel 6 is mounted on a suitable base frame 18. Sides 13 of the vesselpreferably are flat and extend somewhat above the discharge outlets 8 toassist in guiding the sink into troughs 20 arranged adjacent the outletsat the respective ends of the arcuate path of the rake. Verticalsupporting columns, comprising pairs of opposed channel irons 21, 21,are secured at opposite sides of the vessel or frame and extend for somedistance above the vessel. Arranged for vertical movement within thecrosshead guide channels provided by these columns are crosshead bearingblocks 22, 22, best shown in Fig. 2, xedly attached to screws 23, 23,which in turn engage chain sprockets 24 rotating in supports 24aattached to cross beam 25 fixed to the upper ends of channel irons 21,21, with suitable bracing'such as provided by gusset plates 26. ChannelsV21, 21, preferably are braced to the frame 18, as by means of diagonalsupports 27, 27.

The crossheadY bearing blocks carry the pivotal mounting for rake arms12 and also a fixed mounting for baille 1G. In the specific constructionshown, the pivotal mounting for the rake comprises an axle rod 28extending into the crosshead bearing blocks. Rake arms 12 are fixed toaxle rod 2S for oscillatory movement therewith as imparted by gearsector 29 fixed to the axle rod in cooperation with other mechanism tobe described. Also fixed to axle rod 28 is a counterweight 72 whichbalances the weight of the rake and its supporting arms about the axisof oscillation, decreasing the amount of power required for operatingthe rake. The fixed mounting for baie 10 comprises a pair of anglebrackets 30 each having a horizontal arm resting on the respectivecrosshead block 22 and a pair of legs 31, 31, straddling axle rod 28,these legs being secured to upward extensions 32, 32 of side walls ofthe baffle. The chain sprockets 24 at the upper ends of screws 23, 23are connected by drive chain 33. A bevel gear 34, as part of one of thesprockets 24, meshes with another bevel gear 35 fixed to rod 36 mountedin bearings suitably supported on beam 25. A chain drive 37 turns rod 36in either direction to raise and lower crosshead blocks 22, 22, throughthe drive mechanism justdescribed, as desired. When these blocks areraised, they carry with them both the rake 7 and baffle 10 so that theseelements can be lifted free and clear of the vessel 6, for cleaning andrepairs.

The mechanism for operating the rake comprises,.in addition to gearsector 29 to which reference has been made, a rack 38 meshing with thegear sector and fixed to piston rod 39 of a double-acting air orhydraulic cylinder 40 mounted on a support 41 carried on a bracket 42fixed to one of the columns made up of channel irons 21, 2l. Alsomounted on support 41 is a pair of channel irons 45, 45, engaged byC-shaped slides 46, 46 which have threaded engagement with an adjustingrod 47, one end of which is threaded right-hand and the other lefthand.This adjusting rod is mounted for rotation in a bearing block V48 andheld against endwise movement relative' thereto by suitable collars orthrust bearings. B y turning a hand wheel 49 fixed to the adjusting rod47, slides 46, 46 can be moved closer together or farther apart topositions selected for automatic control of the oscillatory movements ofrake 7. Each of the slides 46 carries a normally open electric limitswitch, one ofwhich wefhere designate 50 and the other S1. Theseswitches are operated by a stop 52 fixed to piston rod 39 in suchposition that when rake 7 is at the mid-point of its oscillation, stop52 will be half way between switch 50 and switch 51.

ln Fig. we have illustrated diagrammatically one form'of-automaticcontrol for the rake operating mechanism.'-` `The ends of operatingcylinder 40 are connected, respectively, by' uid conduits 43 and 44 tospeed control valves 53 and 54; `and thence through master control 4valves 55 and 56 to a manifolded fluid pressure source indicated at 57.The electric limit switches selectively operate master control valves 55and 56 through solenoids 58 and 59, actuating valve 60. The closing oflimit switch 50 by stop 52 at the end of the upward movement of rack 38has actuated solenoid 58 to move the piston assembly 61 of valve 60 intothe position shown in Fig. 5, where it will remain until the other limitswitch, 51, is closed. In this position master valve 56 is connected tothe source of uid pressure 57 through valve 60. This has opened valve 56to admit fluid under pressure from conduit 57 into conduit 43, and hasoperated valve 55 to permit fluid to low from conduit 44 to exhaustconduit 62. Thus, under the conditions stated high pressure fluid entersthe upper end of cylinder 40, and low pressure fluid flows from thelower end of such cylinder, causing piston rod 39 to be propelleddownwardly. This in turn results in moving rake 7 in the direction ofarrow a. As the rake reaches the limit of this movement, i. e. theposition shown in Fig. l, the other limit switch, 5l, is closed,actuating solenoid 59. This moves piston assembly 61 of valve 60 to theright as viewed in Fig. 5 and the entire operation described above isreversed. In this manner the rake is caused to oscillate slowly back andforth through the separatory vessel.

In our preferred construction shown, the blade 63 of the rake (cf. Fig.4) is pivotally mounted at 64 on section 14 of supporting arm 12 withthe free edge of the blade adjacent the inner surface of the vessel-orin this case against a rubber lining 65 comprising such inner surface.The blade 63 preferably is T-shaped in cross-section and may have rubberwiper strips 66 forming its free edge. Stops 67, 67 projecting inwardlyfrom supporting arms 12 engage the ends of the rake to limit the extentof its movement around pivotal mounting 64. Moving. in the direction ofarrow a the blade 63 assumes the position shown in Fig. l.. Moving .inthe direction of arrow a', it assumes the position shown in Fig. 4. Notethe favorable angle of inclination of the blade for discharge of sinkinto trough 20 as depicted in Fig. 1. Due to the pivotal mounting, anequally favorable angle of inclination Vis obtained when the rakereaches its limit of movement in the opposite direction. Material to beprocessed in the separator may be fed into the vessel by a chute 68mounted by a bracket 69` on frame 18. In Figs. 2 and 3 may be notedextensions 70 and 71 of the sink discharge troughs 20 and floatdischarge trough 17, respectively. Trough 17 fits into extension 71 insuch a way that when the rake and bae with associated trough structureare lifted by means of the mechanism earlier described, trough 17 freelydisengages itself from extension 71.

The speed of operation of the rake may be varied in accordance with thetype of material being processed, i. e. in relation to the normal timerequired for separation, rate of feed, etc. For example a speed of 8discharges per minute, or 4 discharges to each side per minute may beconsidered satisfactory for most purposes. The speed control valves 53and 54 are adjustable to give the desired speedof operation forparticular conditions to be met in a particular instance.

The terms and expressions Vwhich We have employed are used inadescriptive and not a limiting sense, and we have no intention ofexcluding such equivalents of theinvention described, or of portionsthereof, as fall within the purview of the claims.

We claim:

l. Apparatus for gravity separation of materials in liquid media,comprising a vessel to contain a pool of liquid medium, said vesselbeing of generally arcuate form in vertical section, a rake mounted foroscillation Vwith reference toa horizontal axis located above thesurface of the pool so that the rake moves in a generally arcuate'pathladjacent'the inner surface of the vessel,

discharge outlets at the respective ends of said arcuate path, said rakeserving to move sunken material from the bottom of the vessel to saiddischarge outlets, and a. discharge Weir for material suspended in theliquid medium.

2. Apparatus for gravity separation of materials in liquid media,comprising a vessel to contain a pool of liquid medium, said vesselbeing of generally arcuate form in vertical section, a rake suspendedfrom a pivotal mounting located above the surface of the pool to moveback and forth along the inner surface of the vessel, discharge outletsat the respective ends of the arcuate path of movement of the rake, saidrake serving to move sunken material from the bottom of the vessel tosaid discharge outlets, and a discharge weir for material suspended inthe liquid medium.

3. Apparatus for gravity separation of materials in liquid media,comprising a vessel which is of generally arcuate form in verticalsection, a bafe encircling a pool for oating material within the vessel,a discharge Weir for the floating material, said discharge Weir beingconnected to said baille and arranged in communication with the pool offloating material encircled by said baffle, and a rake suspended from apivotal mounting located above the surface of the pool to move back andforth in a generally arcuate path along the inner surface of the vesselto move sunken material from the bottom of the vessel to dischargeoutlets at the respective ends of said arcuate path, said rake beingmounted on an oscillatory supporting arm extending between said bailleand the sides of said vessel.

4. Apparatus for gravity separation of materials in liquid media,comprising a vessel which is of generally arcuate form in verticalsection, a bae encircling a pool for floating material within thevessel, a discharge Weir for the floating material, said discharge weirbeing connected to said baie and arranged in communication with the poolof floating material encircled by said bafe, a rake suspended from apivotal mounting located above the surface of the pool to move back andforth in a generally arcuate path along the inner surface of the vesselto move sunken material from the bottom of the vessel to dischargeoutlets at the respective ends of said arcuate path, said rake beingmounted on an arm which extends for some distance in the generaldirection of said arcuate path and thence radially with respect to suchpath to said pivotal mounting above said vessel, and a trough extendingfrom said discharge Weir for floating material, said trough extendingabove said arm 6 when the rake is at one end of its arcuate path ofmovement.

S. Apparatus for gravity separation of materials in liquid media,comprising a vessel which is of generally arcuate form in verticalsection, a bae encircling a pool for floating material within thevessel, a discharge Weir for the oating material, said discharge weirbeing connected to said baflle and arranged in communication with thepool of floating material encircled by said bale, a rake suspended froma pivotal mounting located above the surface of the pool to move backand forth in a generally arcuate path along the inner surface of thevessel to move sunken material from the bottom of the vessel todischarge outlets at the respective ends of said arcuate path, said rakebeing mounted on an arm which extends for some distance in the generaldirection of said arcuate path and thence radially with respect to suchpath to said pivotal mounting above said vessel, and a trough extendingfrom said discharge weir for floating material, said trough extendingabove said arm when the rake is at one end of its arcuate path ofmovement and said arm extending between said baie and the sides of thevessel.

6. Apparatus for gravity separation of materials in liquid media,comprising a vessel which is of generally arcuate form in verticalsection, and a rake suspended from a pivotal mounting located above thesurface of the pool to move back and forth in a generally arcuate pathalong the inner surface of the vessel to move sunken material from thebottom of the vessel to discharge outlets at the respective ends of saidarcuate path, said rake comprising a supporting arm and a bladeextending at right angles to said arcuate path, said blade beingpivotally mounted on the supporting arm with the free edge of the bladeadjacent the inner surface of the vessel, and stops on said supportingarm to restrict pivotal movement of the blade in either direction.

7. Apparatus for gravity separation of materials in liquid media, asdefined by claim 6 in which said blade is substantially T-shape in crosssection.

References Cited in the le of this patent UNITED STATES PATENTS1,778,256 Hueber Oct. 14, 1930 FOREIGN PATENTS 14,928 Great Britain of1913 496,249 Belgium June 30, 1950

1. APPARATUS FOR GRAVITY SEPARATION OF MATERIALS IN LIQUID MEDIA,COMPRISING A VESSEL TO CONTAIN A POOL OF LIQUID MEDIUM, SAID VESSELBEING OF GENERALLY ARCUATE FORM IN VERTICAL SECTION, A RAKE MOUNTED FOROSCILLATION WITH REFERENCE TO A HORIZONTAL AXIS LOCATED ABOVE THESURFACE OF THE POOL SO THAT THE RAKE MOVES IN A GENERALLY ARCUATE PATHADJACENT THE INNER SURFACE OF THE VESSEL, DISCHARGE OUTLETS AT THERESPECTIVE ENDS OF SAID ARCUATE